Flexible ladder rendered rigid by use



Feb. 25, 1969 A. E. KRUTH FLEXIBLE LADDER RENDERED RIGID BY USE Sheet Filed Feb. 6, 1967 .i I QPNQEWSQW Feb. 25, 1969 A. E. KRUTH 3,429,399

FLEXIBLE LADDER RENDERED RIGID BY USE Filed Feb. 6, 1967 Sheet 2 of 4 X////////% Z///////A Fly 7 Feb. 25, 1969 KRUTH 3,429,399

FLEXIBLE LADDER RENDERED RIGID BY USE Filed Feb. 6, 1967 M/ ME TO? myoQ 5. mvurz/ Sheetiof y Filed Feb. 6, 1967 Feb. 25, 1969 KRUTH 3,429,399

FLEXIBLE LADDER RENDERED RIGID BY USE Sheet 4 of 4 A 7'7'02 may United States Patent 3,429,399 FLEXIBLE LADDER RENDERED RIGID BY USE Andre E. Kruth, 18 Rue de Rome, Verviers, Belgium Filed Feb. 6, 1967, Ser. No. 618,260 Claims priority, applifisation gelgium, Feb. 9, 1966,

U.S. Cl. 182-196 4 Claims Int. Cl. E06c 9/14, 7/08, 7/50 ABSTRACT OF THE DISCLOSURE A flexible and foldable ladder rendered rigid by use, consisting subsantially of three or more cables joined together by ladder rungs in the form of a quadrilateral, one side of which is folded inwards, forming a loop which substitutes the rung proper. The crosspieces of cable are arranged outside the cable. Platforms are arranged alternately to the right and left and a detachable base plate and a device for folding and unfolding the ladder is also provided.

To execute work on the facade of a building or on any vertical wall, there have hitherto principally been used either ladders supported at the bottom or hooked up' at the top or rigid scaffoldings supported at the bottom or movable scaffoldings suspended by cables.

The object of the present invention is a novel means of moving vertically, namely a flexible ladder which has the form of a cage and has the following properties: it becomes rigid simply by the presence of the user, it has practically no limitation to its length other than the factors of usefulness and resistance of the materials, it ensures perfect safety to the user, enabling him to stand with his hands free at the desired height, it permits easy lateral displacement, it can be folded up in a smaller space and reduced volume, it can be set up in a few seconds and it affords no rigid obstacle to the feet of the user.

A flexible and foldable ladder rendered rigid by use constructed according to the invention is characterised in that it consists substantially of three or more cables joined together by polygonal ladder rungs forming a cage inside which the user moves.

According to the invention, the rungs are essentially in the form of a quadrilateral one side of which is folded inwards, forming a loop which constitutes the rung properly speaking.

According to another feature of the invention, crosspieces of cable are arranged outside the cage two for every two rungs.

The invention further provides platforms arranged alternately to the right and left, a detachable baseplate and a device designed for folding and unfolding the ladder.

A ladder according to the invention is described hereinafter on the basis of the attached drawings given by way of example, which show in FIGURES 1 and 2 a side view and front view, respectively, of the ladder suspended to the front of a building;

FIGURE 3 a view of the ladder of FIGURES 1 and 2 folded up;

FIGURE 4 a plan view at a certain level of the ladder of FIGURES 1 and 2;

FIGURES 5 and 6 plan views at two different levels of a ladder according to FIGURES 1 and 2 equipped with rungs with platforms;

FIGURE 7 a plan view at a certain level of a ladder according to the invention equipped with rungs of a different form;

FIGURES 8, 9 and 10 a side view, front view and plan Patented Feb. 25, 1969 view, respectively, of the arrangement for folding and unfolding a ladder according to FIGURES 1 and 2;

FIGURES l1 and 12 a side view and plan view of a variation of the arrangement according to FIGURES 8 to 10 applied to a ladder with platforms;

FIGURES 13 and 14 two views of a movable baseplate to be used with a ladder according to FIGURE 4;

FIGURES 15 and 16 two views of a variation of the movable baseplate, and

FIGURES 17 and 18 an elevational view and plan view, respectively, of the baseplate of FIGURES 13 and 14 in the operative position.

The ladder represented in FIGURES 1 and 2 essentially comprises four cables 1 suspended at four fixed points to the upper part of a building and falling vertically and a certain number of ladder rungs 2 of a particular type such as described hereinafter and connecting the cables 1.

These ladder rungs, made of a hard material, form a cage round the user (FIGURE 4). Each rung consists of a quadrilateral one side 2' of which is folded inwards to form a loop which constitutes the rung properly speaking. The rung properly speaking 2 on which the foot of the user rests is thus the inner part of the bar, the remainder of the bar forming a protection on one side and at the rear whilst the side 2" which remains open due to the folding back of part 2' bears against and may be hooked to the wall along which the user has to operate. The user is thus surrounded in front, at the back and on two sides.

The rigidity of this ladder which is otherwise flexible comes about from the fact that the cable crosspieces 3 arranged outside the cage formed by the rungs 2 and connected to the latter two for every two rungs are kept in the form of a St. Andrews cross by the Weight of the user who, resting on the inner part of the metal rung, forces the latter to take up the horizontal position, thereby ensuring, by virtue of the crosspieces, that the cage above and around him will be vertical while that below him remains flexible.

Access to this ladder is by the open part of the rungs either from below if the ladder reaches down to the ground or from any level by a Window or a ledge on the building. For greater safety, the ladder may be kept attached to the facade, for example by means of small straps fitted with hooks with which it is provided (not shown in the drawings) and which can easily be quickly hooked to projections on the building or windows.

The embodiment shown in FIGURE 4 has only one and the same cage over the whole length of the ladder which is a long ladder without platforms.

Another embodiment shown in FIGURES 5 and 6 comprises a cage alternately on the left and on the right of the user and has safety platforms 4 at regular intervals. It is these platforms 4 which, by being located alternately to the right and left of the cage as a whole, force the user to use the rung portion 2' which remains free. The object of these platforms is to break the fall of the user when necessary, especially in the evacuation of damaged buildings, and partly to eliminate the chance of dizziness by cutting the vertical view from a height. These platforms are fixed alternately at the rate of two per storey so that the platform situated adjacent to the building coincides, if possible, with the window ledges so as to facilitate exit in the case of emergency. In this ladder with tWo alternate cages, the ladder rung properly speaking on which one rests consists of half the folded part 2 of the bar and may differ in form from that described above and shown in FIGURE 4, for example it may be bent twice so that its end rests against the contiguous element of the rung.

It is to be understood that in order to enable the user to move at the side of the platforms in the cages, the ladder of this embodiment must be wider than that of the first embodiment; this has not been shown in the drawings.

A ladder according to the invention may comprise polygonal rungs of many different forms. Another example of rung is shown in FIGURE 7; here, with four cables 1, an I-shaped rung 2 is used, the central arm or core 2' of which serves as the rung properly speaking. It is to be understood that certain of the rungs constituting the ladder, of no matter what form, may be completely closed and others open to permit entry into the cage.

Folding and unfolding of a ladder according to the invention takes place in the manner of a concertina blind. To unfold the ladder, a cable 5 passing through the completely bent part of the rungs descends from a winch 6 on which it was wound and which is mounted in the upper part of the building. This cable 5 is provided with a small hook 7 to which is attached a hairpin bent book 8 which is lowered with the cable 5 and in which the rungs are stacked (see FIGURES 3, 8, 9, When the ladder has been completely unwound, this hook 8 can be detached and in its place it is possible to fix a narrow oblong sort of shelf (not shown) designed to contain tools for various different operations and capable of being raised and lowered inside the loops of the runs so as to accompany the user in his work. When unfolded, the ladder may be attached at the bottom by its last rungs for supplementary rigidity and stability.

To fold up the'latter, the hairpin bent hook 8 is replaced at the end of the cable 5. When the cable is raised by the winch 6, the rungs 2 are evenly stacked in the throat of the hook, the first rung which is adapted to receive all the others being kept in a horizontal position by two plates 9 welded to the loop of the hook 8. For ladders equipped with platforms, a slightly different hook 8 is used, as shown in FIGURES 11 and 12, and instead of the plates 9, a rod 9 is welded to the hook 8.

In one embodiment of the ladder as shown in FIGURE 4, a small movable baseplate or platform may be used. Such a movable platform (see FIGURES 13, 14, 17, 18) comprises a plate 10 provided along one edge with two notches 10' designed to receive two cables opposite the run 2 properly speaking, this side of the plate resting on that part of the rung 2 which is contiguous with the said cables while the opposite side rests on the rung 2 properly speaking, and on its lower surface are a tongue 11 and clamp 11' to fix it between the said parts of the ladder. Once this movable platform is fixed, it provides complete security and enables the user to stay standing or sitting there with both hands completely free. The operator using the ladder carries this platform with him by suspending it to a belt slung across his back from a handle 12 in the form of a pivot hook with which the plate 10 is equipped. By taking hold of the handle 12, the operator can easily deposit the platform or baseplate on the rung immediately below that which supports him.

Ladders according to the invention have many different uses. The following may be given by way of example:

To carry out finishing or inspection work on. surfaces or constructions at a certain height;

To reach a given height in metal frameworks of buildings under construction;

To reach heights or depths safely;

For emergency evacuation of a damaged building by reaching the ground or an undamaged storey;

For evacuating ships passengers into lifeboats;

For boarding a helicopter which cannot land;

For completely safe descend into caves;

For carrying out various maintenance work on the outside of buildings; such as painting, window-cleaning etc.

If the ladder is to be used as a safety ladder, it is obvious that it must be kept permanently folded up in the top storey of the building to be evacuated. In that case, a steel cord running the whole length of the front of the building and accessible by windows is provided to enable the ladder to be unwound immediately.

The examples described above all related to ladders comprising four cables connected by rungs. It should be understood that such ladders could be constructed with three or with more than four cables without going outside the scope of the invention. In that case, the rungs would be formed accordingly to connect the chosen nurn ber of cables. Similarly, the crosspieces could be considered according to the invention to form cables so that not more than two other cables are used.

I claim:

1. Flexible and foldable ladder comprising a plurality of consecutive spaced cages consisting of polygonal frame members having one side bent inwardly, said side forming a rung and having an open side in said cage for ingress and egress of personnel and cable supporting means secured to said cages.

2. Flexible and foldable ladder, as claimed in claim 1, further provided with platforms secured to said respective cages and extending partially of the area thereof, said platforms defining with said cages open portions, the platform of one cage arranged alternately with the open portion of a following cage and cable crosspieces securing consecutive pairs of cages with one another.

3. Flexible and foldable ladder, as claimed in claim 1, further comprising a removable platform plate provided along one edge with notches and clamp means for engaging with said cable means, and a hook pivotably secured to said removable platform for suspending said platform on a belt of a person using said ladder.

4. Flexible and foldable ladder, as claimed in claim 1, further provided with a haulage cable for folding said ladder, an elongated hook secured to one end of said cable for stacking said cages and a plate, the lowermost of said cages being rigidly securely perpendicularly to said hook at the bottom portion thereof.

References Cited UNITED STATES PATENTS 869,959 11/1907 Bryant 182-196 732,946 7/ 1903 Johnson 182196 FOREIGN PATENTS 814,430 6/1959 Great Britain.

962,641 7/1964 Great Britain.

REINALDO P. MACHADO, Primary Examiner. 

